Disconnect switch having internally clamped rotary coupling

ABSTRACT

The hollow tubular rotatable control rod of an electrical disconnect switch is connected to a yoke which effects rotary movement thereof by means of a slotted hollow cylindrical member on the yoke which projects into one end of the hollow rod. Each slot is provided with a taper key located therein. A frustoconical nut is drawn up inside the member on the yoke to cause radial movement of the taper keys and a snug fit between exterior surface of the latter and the interior surface of the rod.

United States Patent Inventor Calvin E. Redfern Portland. Oreg.

Appl. No. 865,758

Filed Oct. 13, 1969 Patented Feb. 9, 1971 Assignee Allis-Chalmers Manufacturing Company Milwaukee, Wis.

DISCONNECT SWITCH HAVING INTERNALLY CLAMPED ROTARY COUPLING 4 Claims, 2 Drawing Figs.

11.8. CI 287/20.3, 287/124 Int. Cl F1611 1/00 Field of Search 287/203, 124, 100; 85/66, 75; 279/2 [56] References Cited UNITED STATES PATENTS 1,432,121 10/1922 Prickett 279/2 2,071,363 2/1937 Shannon 85/75X 2,213,379 9/1940 Bird et al. 279/2UX Re.26,248 8/1967 Anthony 279/2 Primary ExaminerDavid J Williamowsky Assistant Examiner-Andrew V. Kundrat AttorneysThomas F. Kirby, Lee H. Kaiser and Robert B.

Benson ABSTRACT: The hollow tubular rotatable control rod of an electrical disconnect switch is connected to a yoke which effects rotary movement thereof by means of a slotted hollow cylindrical member on the yoke which projects into one end of the hollow rod. Each slot is provided with a taper key located therein. A frustoconical nut is drawn up inside the member on the yoke to cause radial movement of the taper keys and a snug fit between exterior surface of the latter and the interior surface of the rod.

PATENTEU FEB 9197:

SUMMARY OF THE INVENTION This invention relates generally to electrical disconnect switches and, particularly to improved means for connecting the tubular control rod thereof to the yoke which effects rotary movement thereof.

Heretofore, the tubular control rods of some disconnect switches were connected to the yoke which effected rotational movement thereof by means of a member on the yoke which projected into one end of the tubular rod and pins or bolts extended transversely through the blade and the member. However, disconnect switches are sometimes subjected to severe icing conditions which inhibit rotational movement of the rod when attempts are made to operate them and the high rotational forces exerted by the yokes sometimes caused damage to the pins or to the rods adjacent the pins because nearly all stresses were concentrated in these regions. Such damage interferred with proper switch operation and necessitated repair of replacement of the rods or other components.

It is desirable, therefore, to provide improved means for connecting tubular control rods to the operating yokes to overcome the aforementioned difficulties.

In accordance with the present invention there is provided a disconnect switch having a hollow tubular control rod which is connected to an operating yoke by means of a projection on the yoke which is hollow and slotted, which has a taper key in each slot, and which has a frustoconical expansion nut located therein to effect outward radial movement of the taper keys whereby the latter grip the interior of the tubular control rod.

OBJECTS OF THE INVENTION It is an object of the present invention to provide improved disconnect switches.

Another object is to provide improved means for connecting tubular control rods to the rotatable operating yoke in disconnect switches.

Another object is to provide improved means of the aforesaid character which effect equalized distribution of shear or rotational forces at the place where the rod joins the yoke.

Another object is to provide means of the aforesaid character which reduce the number of components, manufacturing operations and assembly steps required in the manufacture of disconnect switches.

Another object is to provide improved disconnect switches which are more reliable in operation and able to operate in severe icing conditions without less risk of damage.

Other objects and advantages of the invention will hereinafter appear.

DESCRIPTION OF THE DRAWINGS The accompanying drawings illustrates a preferred embodiment of the invention but it is to be understood that the embodiment illustrated is susceptible of modification with respect to details thereof without departing from the scope of the appended claims.

In the drawing:

FIG. 1 is a cross-sectional view of a control rod for a disconnect switch embodying the present invention; and

FIG. 2 is a partial cross-sectional view taken along line "-11 of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION Referring to FIG. I of the drawing, the numeral designates a control rod for an electrical disconnect switch in accordance with the present invention. A yoke 18 which is connected to the other end of control rod 10 to effect rotational movement of the latter. As hereinafter explained, yoke 18 is adapted to rotate to effect opening and closing movement of a disconnect switch. During opening and closing movement; yoke 18 is rotated a predetermined angular distance to effect corresponding rotation of rod 10 about its longitudinal axis.

As FIGS. 1 and 2 show, yoke 18 comprises a body section 20 from which two legs 22 and 24 extend and the legs are provided with holes 26 and 28, respectively, by means of which the yoke is secured to a mechanism which rotates it. Body section 20 of yoke 18 is also provided with a member 30 which projects therefrom and with which rod 10 is associated. Member 30, which is preferably integrally formed with body section 20 of yoke 18 by casting or machining, takes the form of a hollow cylinder. The exterior diameter of member 30 is such as to permit it to fit easily but loosely within one end of rod 10 which is hollow and cylindrical. Member 30 is provided with a plurality, in this case three, of evenly spaced apart radially disposed slots 34 which extend entirely through its wall. The hollow interior 36 of member 30 is frustoconical in shape and is adapted to accommodate an expansion nut 38.

Expansion nut 38 is frustoconical in shape and is provided with a threaded hole 40 extending axially therethrough. A bolt 42 extends through an unthreaded hole 44 in the body section 20 of yoke 18 and takes up in threaded hole 40 in expansion nut 38.

Each slot 34 is adapted to receive a taper key 46 which has two projections 48 thereon for engagement with the inner wall surface of rod 10 and a tapered edge or surface 50 for engagement with the exterior surface of nut 38. The taper keys 46 are held in place by means of a retaining wire or split ring 52 in a notch 54 around the circumference of member 30 when the yoke is disassociated from said rod.

During assembly, nut 38 is inserted into hollow interior 36 of member 30 of yoke 18 and bolt 42 is inserted through hole 44 in body section 20 of the yoke and into threaded hole 40 in the nut. Bolt 42 is tightened sufficiently to secure nut 38 in place. The taper keys 46 are then placed in the slots 34 and the wire 52 is put in place. Then, the end of rod 10 is slipped over member 30 of yoke 18 as far as it will go. Finally, bolt 42 is tightened so as to cause expansion nut 38 to be drawn into the interior 36 of member 30. lntemal movement of nut 38 causes taper keys 46 to move radially outward, the slots 34 in member 30 permitting such expansion. As this occurs, the projections 48 on the taper keys 46 tightly engage with the smooth interior cylindrical surface of rod 10 and rod l0 and yoke 18 become firmly connected. Because physical contact occurs at many points, any stresses or forces transmitted from yoke 18 as it is rotated are widely and evenly distributed around the end of rod 10. Thus, any tendency for rod 10 to tear or be deformed is substantially reduced.

Rod 10 can be disconnected from member 30 of yoke 18 by loosening bolt 42 and tapping thereon to drive nut 38 outwardly of the interior 36 of member 30 thereby relieving the pressure between rod 10 and the taper keys 46.

I claim:

1. In a coupling,

a rod having a smooth bored opening extending axially into one end thereof,

a rotatable yoke for rigidly connecting to said rod,

said yoke having a projection with a substantially smooth outer periphery projection thereon extending into said opening,

said projection having a frustoconical opening therein and a plurality of slots therein,

a frustoconical expansion nut in said opening in said projection,

a taper key in each slot, and

a bolt extending through an opening in said yoke for engagement with said nut and rotatable to draw said nut into said projection to cause outward radial movement of said taper keys and their engagement with the wall of the opening in said rod, said frustoconical opening and slots extending the full length of said projection and said taper keys being substantially equal in length to the length of said slots to achieve maximum physical contact and an even distribution of stresses upon transfer of torque from said yoke to said rod.

2. A coupling according to'claim 1 wherein each of said securing said taper keys in said slots when said yoke is disassociated from said rod.

4. A coupling according to claim 3 wherein said means for securing said taper key comprises a wire engageable in a notch taper keys has at least one pro ection thereon for engagement 5 in the projection on Said yoke.

with the wall of said rod.

3. A coupling according to claim 2 including means for 

1. In a coupling, a rod having a smooth bored opening extending axially into one end thereof, a rotatable yoke for rigidly connecting to said rod, said yoke having a projection with a substantially smooth outer periphery projection thereon extending into said opening, said projection having a frustoconical opening therein and a plurality of slots therein, a frustoconical eXpansion nut in said opening in said projection, a taper key in each slot, and a bolt extending through an opening in said yoke for engagement with said nut and rotatable to draw said nut into said projection to cause outward radial movement of said taper keys and their engagement with the wall of the opening in said rod, said frustoconical opening and slots extending the full length of said projection and said taper keys being substantially equal in length to the length of said slots to achieve maximum physical contact and an even distribution of stresses upon transfer of torque from said yoke to said rod.
 2. A coupling according to claim 1 wherein each of said taper keys has at least one projection thereon for engagement with the wall of said rod.
 3. A coupling according to claim 2 including means for securing said taper keys in said slots when said yoke is disassociated from said rod.
 4. A coupling according to claim 3 wherein said means for securing said taper key comprises a wire engageable in a notch in the projection on said yoke. 